1. Field of the Invention
The present invention relates to a display device having a display section including sub-pixels arranged in a delta configuration, and to a technique for increasing display resolution and the like.
2. Description of the Background Art
In many cases, matrix displays having pixels (or picture elements) arranged in a matrix have employed trio arrangement pixels. FIG. 39 is a schematic (plan) view for illustrating the trio arrangement pixels. As shown in FIG. 39, a trio arrangement pixel P is substantially square in shape, and comprises three strip-shaped sub-pixels (or cells) C: a sub-pixel C for red (R), a sub-pixel for blue (B), and a sub-pixel for green (G). The three sub-pixels C extend in a column direction v of a display and are arranged in a row direction h perpendicular to the column direction v.
In general, the trio arrangement pixels are low in resolution considering the number of pixels, but have good linearity in the row direction h and in the column direction v. Therefore, the trio arrangement pixels are suitable for graphic drawing. Additionally, the trio arrangement pixels can display a video image with natural texture. The video image refers to an image produced by optically capturing a subject using a video camera and the like.
FIG. 40 is a schematic (plan) view for illustrating a plasma display panel (also referred to hereinafter as a xe2x80x9cPDPxe2x80x9d) 500 having the trio arrangement pixels. The PDP 500 basically comprises a glass container including a front glass substrate and a rear glass substrate which are disposed in face-to-face relationship, with a discharge gas filling the interior of the container (or a discharge space). The PDP 500 shown in FIG. 40 is an alternating current (AC) PDP.
A plurality of strip-shaped metal electrodes or bus electrode 501 are formed on the front glass substrate and extend in the row direction h. The plurality of bus electrodes 501 are in pairs, and a strip-shaped black stripe 504 is formed between adjacent pairs of the bus electrodes 501. The black stripes 504 decrease an extraneous light reflectance to improve contrast. Transparent electrodes 502 in contact with each of the bus electrodes 501 overhang in the opposite direction from the black stripes 504. The transparent electrodes 502 in contact with one of each pair of bus electrodes 501 are opposed to the transparent electrodes 502 in contact with the other thereof, with a discharge gap 503 therebetween. Each of the bus electrodes 501 and the transparent electrodes 502 connected thereto are collectively referred to also as a xe2x80x9crow electrodexe2x80x9d hereinafter. A pair of row electrodes X1, Y1 and a pair of row electrodes X2, Y2 are shown in FIG. 40.
On the other hand, a plurality of strip-shaped column electrodes or address electrodes are formed on the rear glass substrate and extend in the column direction v (thus so as to intersect the bus electrodes 501 (at different levels)). Six column electrodes W1 to W6 are shown in FIG. 40. A strip-shaped barrier rib (also referred to simply as a xe2x80x9cribxe2x80x9d hereinafter) 505 is formed between adjacent ones of the column electrodes on the rear glass substrate. Each rib 505 is formed so as to separate the transparent electrodes 502 adjacent in the row direction h from each other or so as to partition the interior of the glass container. A phosphor 506R, 506B or 506G for red (R), blue (B) or green (G) is formed to cover each of the column electrodes W1 to W6.
A sub-pixel C in the PDP 500 has an area defined by adjacent ones of the barrier ribs 505 and adjacent ones of the black stripes 504. Three sub-pixels C adjacent in the row direction h and emitting red (R), blue (B) and green (G), respectively, constitute one pixel P (see FIG. 39).
The PDP 500 which has no ribs extending in the row direction h is easy to manufacture, but must ensure a distance between adjacent electrode pairs to prevent interference of discharge between rows or between sub-pixels C arranged in the column direction v. Thus, the PDP 500 has a display problem such that an image of a slant line, when displayed, appears jagged. This display problem becomes more noticeable when a slant line has a smaller slope with respect to the row direction h or when the PDP 500 has the black stripes 504.
In general, the AC PDP 500 is driven through a series of operations including a reset operation, an address operation, a display operation (or a sustain operation) and an erase operation. More specifically, the electric charge state in the PDP 500 (i.e., in all discharge cells) is initialized during a reset period (the reset operation).
During an address period, image data is given in the form of the presence/absence of electric charge (or wall charge) into each of the sub-pixels C. More specifically, scan pulses are applied sequentially to the row electrodes Y1 and Y2 (or potential differences are applied sequentially between electrode pairs), and application/non-application of address pulses or write pulses to the column electrodes W1 to W6 is driven in accordance with data corresponding to the respective sub-pixels C in the image data in synchronism with the sequential application of the scan pulses.
Thereafter, during a display period, repeated discharge (display discharge or sustain discharge) is caused to occur by the use of the wall charge to permit display (the display operation). In this operation, the luminance of each sub-pixel C is controlled by the number of times the discharge is repeated during the display period. During an erase period, the wall charge is erased (the erase operation).
The PDP 500 is capable of representing gradation levels using a driving method referred to as a sub-field gradation (or tone) method (or simply as a sub-field method). In the sub-field gradation method, one sub-field (SF) is formed including the reset operation, the address operation, the display operation and the erase operation, and a plurality of sub-fields are combined together to form one frame (or field). The display periods of the respective sub-fields are made different from each other in the number of times the display discharge is repeated.
FIGS. 41 and 42 are schematic (plan) views for illustrating a PDP 550 having delta arrangement pixels. FIGS. 41 and 42 are disclosed in Proceedings of The 6th International Display Workshops, 1999, p. 599. Like the PDP 500 of FIG. 40, the PDP 550 comprises row electrodes X, Ynxe2x88x921, Yn, Yn+1, column electrodes W1 to W11, and the like. Ribs 555 in the PDP 550 extend in the column direction v while meandering. Because of the shape of the ribs 555, three sub-pixels C constituting one pixel P (see the triangles indicated by broken lines in FIG. 42) in the PDP 550 are disposed to define a triangle. A plurality of pixels P in the PDP 550 are arranged in a matrix throughout the panel.
The delta arrangement allows a sub-pixel C serving as a unit for emitting light to be designed to have a greater width than does the trio arrangement, and therefore is advantageous in the PDP from the viewpoint of light emitting efficiency over the trio arrangement having the elongated sub-pixels C. This is because a narrower discharge space of each sub-pixel (or discharge cell) results in greater energy losses of excited particles such as ions and electrons due to collision with the ribs and the like.
The delta arrangement pixels are also used in a small-sized head mounted liquid crystal display (LCD), a low-cost projection LCD, and the like.
The PDP 550 is driven in a similar manner to the PDP 500 of FIG. 40. More specifically, as shown in FIG. 41, scan pulses are applied sequentially to the row electrodes Ynxe2x88x921, Yn, Yn+1, and the application/non-application of voltages to the column electrodes W1 to W11 is driven in accordance with data corresponding to the respective sub-pixels C in image data in synchronism with the sequential application of the scan pulses. A common voltage is applied to a plurality of row electrodes X.
It is generally known that a display problem referred to as a false contour of a moving picture (color deviation) occurs in the sub-field gradation method. The sub-field gradation method controls luminance by the use of the fact that light emitted for each sub-field is integrated over time on a viewer""s retina. When an image moves on a screen, the viewer""s eye tracks the image to cause a position shift of the time integration, resulting in the observation of the false contour of the moving picture.
The false contour of the moving picture can be suppressed by the use of a greater number of sub-fields than necessary for display of gradation. This method has been used in general. However, this method presents the problem of increased power required for the address operations because of the increased number of times of writing of image data, that is, the increased number of address operations. The increased power gives rise to another problem in cooling of an address IC and the like. Further, as the number of sub-fields increases, the display period becomes shorter, which leads to the reduction in display luminance.
Moreover, the delta arrangement pixels generally have high resolution considering the number of pixels, but has the drawback of lower linearity in the row direction h and in the column direction v than the trio arrangement pixels. In the case of the delta arrangement pixels, as illustrated in FIGS. 41 and 42, sub-pixels C of the same display color in pixels P arranged in the row direction h are displaced in relation to one another (or staggered) in the column direction v. For this reason, when, for example, a horizontal line of a single color extending in the row direction h is displayed, the image of the line appears jagged (which is visually perceived as image noises in the row direction h). Such a display problem is more noticeable when the number of rows is, for example, as small as about 500 or when the viewer near the PDP 550 views the image. Furthermore, an image displayed using the delta arrangement pixels has a lower level of texture than that displayed using the trio arrangement pixels.
According to a first aspect of the present invention, a display device comprises: a display section including a plurality of sub-pixels and having a predetermined screen region in which the plurality of sub-pixels are arranged in a delta configuration; and a drive controller connected to the display section for acquiring image data about an image to be displayed to drive the plurality of sub-pixels based on the image data by using a sub-field gradation method, wherein the plurality of sub-pixels include first, second and third sub-pixels adjacent to each other to define a triangle, and a fourth sub-pixel adjacent to the first to third sub-pixels and located on the opposite side to the third sub-pixed with respect to a line passing through the first and second sub-pixels to define a triangle in conjunction with the first and second sub-pixels, and wherein the drive controller changes a display mode for each the image data between a first display mode in which a first sub-pixel group including the first, second and third sub-pixels constitutes one pixel and a second display mode in which a second sub-pixel group including the first, second and fourth sub-pixels constitutes one pixel.
Preferably, according to a second aspect of the present invention, in the display device of the first aspect, the first sub-pixel is capable of emitting red; the second sub-pixel is capable of emitting blue; and the third and fourth sub-pixels are capable of emitting green.
Preferably, according to a third aspect of the present invention, in the display device of the first or second aspect, the plurality of sub-pixels further include fifth and sixth sub-pixels defining, in conjunction with the first and second sub-pixels, a quadrangle around the third sub-pixel; the first sub-pixel group further includes the fifth and sixth sub-pixels; and the second sub-pixel group further includes the third sub-pixel.
Preferably, according to a fourth aspect of the present invention, in the display device of the third aspect, the fifth sub-pixel is located on the same side as the first sub-pixel with respect to a line passing through the third and fourth sub-pixels, and is capable of emitting the same display color as the first sub-pixel; and the sixth sub-pixel is located on the same side as the second sub-pixel with respect to the line passing through the third and fourth sub-pixels, and is capable of emitting the same display color as the second sub-pixel.
Preferably, according to a fifth aspect of the present invention, in the display device of any one of the first to fourth aspects, the image data corresponds to an interlace signal of the image; and the drive controller uses the first display mode for a first field of the interlace signal, and uses the second display mode for a second field of the interlace signal.
According to a sixth aspect of the present invention, a display device comprises: a display section including a plurality of pixels and having a predetermined screen region formed by the plurality of pixels; and a drive controller connected to the display section for acquiring image data about an image to be displayed to drive the plurality of pixels based on the image data by using a sub-field gradation method, wherein the display section further includes a plurality of sub-pixels disposed in a plurality of rows each extending in a first direction, the plurality of rows being arranged in a second direction perpendicular to the first direction, the plurality of sub-pixels being arranged in a delta configuration to define the predetermined screen region, wherein each of the plurality of pixels comprises three adjacent sub-pixels disposed in two adjacent rows out of the plurality of rows and defining a triangle, wherein the image data includes a plurality of row data corresponding to at least one group of rows selected between a group of odd-numbered rows and a group of even-numbered rows among the plurality of rows, and wherein the drive controller generates interpolation data from at least two of the plurality of row data corresponding to at least two of the plurality of rows, and drives some of the plurality of sub-pixels which are disposed in at least one group of rows selected between the group of odd-numbered rows and the group of even-numbered rows, based on the interpolation data.
Preferably, according to a seventh aspect of the present invention, in the display device of the sixth aspect, the image data corresponds to an interlace signal of the image, and the plurality of row data correspond to the group of odd-numbered rows or the group of even-numbered rows; and the drive controller drives sub-pixels in the odd-numbered rows or in the even-numbered rows, based on the image data acquired, and drives sub-pixels in the even-numbered rows or in the odd-numbered rows, based on the interpolation data.
Preferably, according to an eighth aspect of the present invention, in the display device of the sixth aspect, the image data corresponds to a progressive signal of the image, and the plurality of row data correspond to the plurality of rows; and the drive controller drives the plurality of sub-pixels based on the interpolation data.
Preferably, according to a ninth aspect of the present invention, in the display device of the sixth aspect, the drive controller assigns weights to at least three of the plurality of row data corresponding to at least three of the plurality of rows to generate the interpolation data from the at least three row data.
Preferably, according to a tenth aspect of the present invention, in the display device of the sixth aspect, the drive controller acquires interlace signals for two successive fields to generate the image data including the plurality of row data corresponding to the odd-numbered rows and the even-numbered rows from the two interlace signals; the plurality of row data correspond to the plurality of rows; and the drive controller drives the plurality of sub-pixels based on the interpolation data.
Preferably, according to an eleventh aspect of the present invention, in the display device of any one of the first to tenth aspects, the display section has a screen including the predetermined screen region as a portion thereof; the image includes a still picture region and a moving picture region; and the drive controller displays the moving picture region on the predetermined screen region.
According to a twelfth aspect of the present invention, a display device comprises: a display section including a plurality of pixels and having a predetermined screen region formed by the plurality of pixels; and a drive controller connected to the display section for acquiring image data about an image to be displayed to drive the plurality of pixels based on the image data by using a sub-field gradation method, wherein the display section further includes a plurality of sub-pixels disposed in a plurality of rows each extending in a first direction, the plurality of rows being arranged in a second direction perpendicular to the first direction, the plurality of sub-pixels being arranged in a delta configuration to define the predetermined screen region, wherein each of the plurality of pixels comprises three adjacent sub-pixels disposed in two adjacent rows out of the plurality of rows and defining a triangle, wherein the image data corresponds to an interlace signal of the image, and wherein the drive controller drives some of the plurality of sub-pixels which are disposed either in odd-numbered rows or in even-numbered rows, based on the acquired image data, and drives some of the plurality of sub-pixels which are disposed either in even-numbered rows or in odd-numbered rows, based on image data having been acquired prior to the acquired image data.
According to a thirteenth aspect of the present invention, a display device comprises: a display section including a plurality of sub-pixels and having a predetermined screen region in which the plurality of sub-pixels are arranged in a delta configuration; and a drive controller connected to the display section for acquiring image data about an image to be displayed to drive the plurality of sub-pixels based on the image data by using a sub-field gradation method, wherein the plurality of sub-pixels include a first sub-pixel capable of emitting a first color, a second sub-pixel capable of emitting a second color different from the first color, and a third sub-pixel capable of emitting a third color different from the first and second colors, the first to third sub-pixels being adjacent to each other to define a triangle, thereby forming one pixel, wherein the image data includes data for the first to third colors about a first point and a second point adjacent to each other on the image, and wherein the drive controller drives the first and second sub-pixels based on the data for the first and second colors about the first point, and drives the third sub-pixel based on the data for the third color about the second point.
According to a fourteenth aspect of the present invention, a display device comprises: a display section having a predetermined screen region in which a plurality of sub-pixels are arranged in a delta configuration; and a drive controller connected to the display section for acquiring image data about an image to be displayed to drive the plurality of sub-pixels based on the image data by using a sub-field gradation method, wherein the plurality of sub-pixels include a plurality of central sub-pixels disposed in a plurality of rows each extending in a first direction, the plurality of rows being arranged in a second direction perpendicular to the first direction, and a plurality of peripheral pixels disposed in the plurality of rows to surround each of the plurality of central sub-pixels, wherein the image data includes a plurality of row data corresponding to the plurality of rows, wherein the drive controller drives each of the plurality of central sub-pixels using row data corresponding to a row in which each of the plurality of central sub-pixels is disposed, and wherein the drive controller generates display data using the row data corresponding to each of the plurality of central sub-pixels and row data about rows near the row in which each of the plurality of central sub-pixels is disposed, thereby to drive the peripheral sub-pixels using the display data.
Preferably, according to a fifteenth aspect of the present invention, in the display device of the fourteenth aspect, the plurality of central sub-pixels are capable of emitting a display color of higher luminance than the plurality of peripheral sub-pixels.
Preferably, according to a sixteenth aspect of the present invention, in the display device of the fourteenth or fifteenth aspect, the central sub-pixels are capable of emitting green, and the peripheral sub-pixels are capable of emitting red and blue.
According to a seventeenth aspect of the present invention, a display device comprises: a display section including a plurality of sub-pixels and having a predetermined screen region in which the plurality of sub-pixels are arranged in a delta configuration; and a drive controller connected to the display section for acquiring image data about an image to be displayed to drive the plurality of sub-pixels based on the image data by using a sub-field gradation method, wherein the drive controller samples data corresponding to display colors of at least certain ones of the plurality of sub-pixels from an input signal in a timed relationship corresponding to a relative positional relationship of the at least certain ones of the plurality of sub-pixels in the predetermined screen region, to generate the image data.
The display device according to the first aspect of the present invention can relieve the problem of the false contour of a moving picture, and display an image at higher resolution than a display device having so-called trio arrangement pixels.
According to the second aspect of the present invention, if a change is made between the first display mode and the second display mode, the amounts of movement of the centroid of luminance are approximately equal. This accomplishes so-called pseudo-interlace display in visually natural manner to improve the resolution in a direction of a line passing through the third and fourth sub-pixels.
The display device according to the third aspect of the present invention can produce the above-mentioned effects of the first aspect more remarkably.
The display device according to the fourth aspect of the present invention can produce the above-mentioned effects of the second aspect more remarkably.
The display device according to the fifth aspect of the present invention can produce the above-mentioned effects of the first to fourth aspects in the pseudo-interlace display.
In the display device according to the sixth aspect of the present invention, image noises and the false contour of the moving picture in the second direction are difficult to occur, and natural texture is provided. Additionally, color deviation is prevented.
The display device according to the seventh aspect of the present invention can produce the above-mentioned effects of the sixth aspect when the image data corresponds to the interlace signal.
The display device according to the eighth aspect of the present invention can produce the above-mentioned effects of the sixth aspect when the image data corresponds to the progressive signal.
The display device according to the ninth aspect of the present invention can prevent the color deviation, and display an image faithful to an original signal with soft-looking image quality
The display device according to the tenth aspect of the present invention can display an image having data in only one of the two fields without flicker.
The display device according to the eleventh aspect of the present invention can improve the resolution of the moving picture region in a driving method in which there arises a delay when displaying a moving picture.
The display device according to the twelfth aspect of the present invention can display an image at high resolution without the image noises in the second direction and the false contour of the moving picture.
The display device according to the thirteenth aspect of the present invention can produce a sharp image and relieve the problem of the false contour of the moving picture.
In the display device according to the fourteenth aspect of the present invention, each of the central sub-pixels is driven based on the row data corresponding to the row in which each of the central sub-pixels is disposed. Therefore, an image whose vertical resolution is difficult to improve in the pseudo-interlace is displayed at high resolution.
In the display device according to the fifteenth aspect of the present invention, the central sub-pixels are higher in luminance than the peripheral sub-pixels. This increases luminance resolution to consequently achieve higher-resolution display.
The display device according to the sixteenth aspect of the present invention can easily provide the image quality with a practicable level of resolution in many cases since green is in general higher in luminance.
The display device according to the seventeenth aspect of the present invention can relieve such problems as color deviation and chromatic blur, as compared with a technique in which data about the respective colors in one pixel are separated and assigned to the sub-pixels.
It is therefore an object of the present invention to provide a display device including a display section having sub-pixels arranged in a delta configuration which is capable of displaying a high-definition and high-quality image.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.